Change loops to iterators.

src/api/json.rs

@@ -166,10 +166,7 @@ pub fn format_map_as_json(map: &Map) -> String {
 
         if let Some(val) = value.read_lock::<Map>() {
             result.push_str(&format_map_as_json(&*val));
-            continue;
-        }
-
-        if value.is::<()>() {
+        } else if value.is::<()>() {
             result.push_str("null");
         } else {
             write!(result, "{:?}", value).unwrap();